
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<ul>
    {% for i in alist %}
        <li>{{ loop.index }}-{{ loop.index0 }}
            -{{ loop.revindex }}-{{ loop.revindex0 }}
            -{{ loop.first }}-{{ loop.last }}
            -{{ loop.length }}-{{ i }}</li>
    {% endfor %}
</ul>
<ul>
    {% for i in alist %}
        <li style="background-color: {{ loop.cycle('#fff','#ccc', '#999') }}">
            {{ i | c }}
        </li>
    {% endfor %}

</ul>

{% load xxx %}
{{ abc | default:'abc' }}

{#不用load#}
{{ abc | default('abc') }}

</body>
</html>